Susan Levin

Dietary and lifestyle guidelines for the prevention of Alzheimer's disease.

Risk of developing Alzheimers disease is increased by older age, genetic factors, and several medical risk factors. Studies have also suggested that dietary and lifestyle factors may influence risk, raising the possibility that preventive strategies may be effective. This body of research is incomplete. However, because the most scientifically supported lifestyle factors for Alzheimers disease are known factors for cardiovascular diseases and diabetes, it is reasonable to provide preliminary guidance to help individuals who wish to reduce their risk. At the International Conference on Nutrition and the Brain, Washington, DC, July 19-20, 2013, speakers were asked to comment on possible guidelines for Alzheimers disease prevention, with an aim of developing a set of practical, albeit preliminary, steps to be recommended to members of the public. From this discussion, 7 guidelines emerged related to healthful diet and exercise habits.

Position of the Academy of Nutrition and Dietetics: Vegetarian Diets

It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with much less environmental damage. Vegetarians and vegans are at reduced risk of certain health conditions, including ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity. Low intake of saturated fat and high intakes of vegetables, fruits, whole grains, legumes, soy products, nuts, and seeds (all rich in fiber and phytochemicals) are characteristics of vegetarian and vegan diets that produce lower total and low-density lipoprotein cholesterol levels and better serum glucose control. These factors contribute to reduction of chronic disease. Vegans need reliable sources of vitamin B-12, such as fortified foods or supplements.

Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis

INTRODUCTION Previous studies have suggested an association between vegetarian diets and improvements in glycemic control in diabetes, although this relationship is not well established. No meta-analysis of these studies has been performed. METHODS To conduct a systematic review and meta-analysis of controlled clinical trials examining the association between vegetarian diets and glycemic control in type 2 diabetes. DATA SOURCE The electronic databases Medline, Web of Science, Excerpta Medica Database (EMBASE), and Cochrane Central Register of Controlled Trials were searched for articles published in any language through December 9, 2013. STUDY SELECTION The following criteria were used for study inclusion: (I) age of participants >20 years; (II) vegetarian diet as intervention; (III) mean difference in hemoglobin A1c (HbA1c) and/or fasting blood glucose levels used as outcomes; and (IV) controlled trials, duration ≥4 weeks. Exclusion criteria were: (I) not an original investigation; (II) duplicate samples; (III) diabetes other than type 2; (IV) multiple interventions; and (V) uncontrolled studies. DATA EXTRACTION AND SYNTHESIS The data collected included study design, baseline population characteristics, dietary data, and outcomes. Data were pooled using a random-effects model. MAIN OUTCOMES AND MEASURES Differences in HbA1c and fasting blood glucose levels associated with vegetarian diets were assessed. RESULTS Of 477 studies identified, six met the inclusion criteria (n=255, mean age 42.5 years). Consumption of vegetarian diets was associated with a significant reduction in HbA1c [-0.39 percentage point; 95% confidence interval (CI), -0.62 to -0.15; P=0.001; I(2)=3.0; P for heterogeneity =0.389], and a non-significant reduction in fasting blood glucose concentration (-0.36 mmol/L; 95% CI, -1.04 to 0.32; P=0.301; I(2)=0; P for heterogeneity =0.710), compared with consumption of comparator diets. CONCLUSIONS Consumption of vegetarian diets is associated with improved glycemic control in type 2 diabetes. PROSPERO registration number is CRD42013004370.

A multicenter randomized controlled trial of a plant-based nutrition program to reduce body weight and cardiovascular risk in the corporate setting: the GEICO study

Background/objectives:To determine the effects of a low-fat plant-based diet program on anthropometric and biochemical measures in a multicenter corporate setting.Subjects/methods:Employees from 10 sites of a major US company with body mass index ⩾25 kg/m2 and/or previous diagnosis of type 2 diabetes were randomized to either follow a low-fat vegan diet, with weekly group support and work cafeteria options available, or make no diet changes for 18 weeks. Dietary intake, body weight, plasma lipid concentrations, blood pressure and glycated hemoglobin (HbA1C) were determined at baseline and 18 weeks.Results:Mean body weight fell 2.9 kg and 0.06 kg in the intervention and control groups, respectively (P<0.001). Total and low-density lipoprotein (LDL) cholesterol fell 8.0 and 8.1 mg/dl in the intervention group and 0.01 and 0.9 mg/dl in the control group (P<0.01). HbA1C fell 0.6 percentage point and 0.08 percentage point in the intervention and control group, respectively (P<0.01).Among study completers, mean changes in body weight were −4.3 kg and −0.08 kg in the intervention and control groups, respectively (P<0.001). Total and LDL cholesterol fell 13.7 and 13.0 mg/dl in the intervention group and 1.3 and 1.7 mg/dl in the control group (P<0.001). HbA1C levels decreased 0.7 percentage point and 0.1 percentage point in the intervention and control group, respectively (P<0.01).Conclusions:An 18-week dietary intervention using a low-fat plant-based diet in a corporate setting improves body weight, plasma lipids, and, in individuals with diabetes, glycemic control.

A Multicomponent Intervention Reduces Body Weight and Cardiovascular Risk at a GEICO Corporate Site

Purpose. To determine whether a multicomponent nutrition intervention program at a corporate site reduces body weight and improves other cardiovascular risk factors in overweight individuals. Design. Prospective clinical intervention study. Subjects/Setting. Employees of the Government Employees Insurance Company (GEICO) (N = 113), aged 21 to 65 years, with a body mass index ≥ 25 kg/m2 and/or previous diagnosis of type 2 diabetes. Intervention. A 22-week intervention including a low-fat, vegan diet. Measures. Changes in body weight, anthropometric measures, blood pressure, lipid profile, and dietary intake. Analysis. Multivariate analyses of variance were calculated for clinical and nutrient measures, followed by univariate analyses of variance, to determine the significance of differences between groups in changes over time. Results. Intervention-group participants experienced greater weight changes compared with control-group participants (mean, – 5.1 [SE, .6] kg vs. + .1 [SE, .6] kg, p < .0001), as well as greater changes in waist circumference (mean, – 4.7 [SE, .6] cm vs. + .8 [SE, .6] cm, p < .0001) and waist:hip ratio (mean, – .006 [SE, .003] vs. + .014 [SE, .005], p = .0007). Weight loss of 5% of body weight was more frequently observed in the intervention group (48.5%) compared with the control group (11.1%) (χ2[1, N= 113] = 16.99, p < .0001). Conclusions. Among individuals volunteering for a 22-week worksite research study, an intervention using a low-fat, vegan diet effectively reduced body weight and waist circumference.

Meat Consumption as a Risk Factor for Type 2 Diabetes

Disease risk factors identified in epidemiological studies serve as important public health tools, helping clinicians identify individuals who may benefit from more aggressive screening or risk-modification procedures, allowing policymakers to prioritize intervention programs, and encouraging at-risk individuals to modify behavior and improve their health. These factors have been based primarily on evidence from cross-sectional and prospective studies, as most do not lend themselves to randomized trials. While some risk factors are not modifiable, eating habits are subject to change through both individual action and broader policy initiatives. Meat consumption has been frequently investigated as a variable associated with diabetes risk, but it has not yet been described as a diabetes risk factor. In this article, we evaluate the evidence supporting the use of meat consumption as a clinically useful risk factor for type 2 diabetes, based on studies evaluating the risks associated with meat consumption as a categorical dietary characteristic (i.e., meat consumption versus no meat consumption), as a scalar variable (i.e., gradations of meat consumption), or as part of a broader dietary pattern.

Applying the Precautionary Principle to Nutrition and Cancer

Primary Objective: Research has identified certain foods and dietary patterns that are associated with reduced cancer risk and improved survival after cancer diagnosis. This research has formed the basis for dietary guidance issued by cancer organizations. Unfortunately, gaps within nutrition research have made it difficult to make recommendations in some areas. This review specifies suggested dietary guidance in which evidence of a dietary influence on cancer risk is substantial, even if not conclusive. Evidence summaries within the review are based on the 2007 report of the World Cancer Research Fund/American Institute for Cancer Research. This review also describes advantages and disadvantages of following the suggested dietary guidance and includes putative mechanisms involved in cancer progression. Main Outcomes and Results: Suggested dietary guidance where evidence is sufficiently compelling include (1) limiting or avoiding dairy products to reduce the risk of prostate cancer; (2) limiting or avoiding alcohol to reduce the risk of cancers of the mouth, pharynx, larynx, esophagus, colon, rectum, and breast; (3) avoiding red and processed meat to reduce the risk of cancers of the colon and rectum; (4) avoiding grilled, fried, and broiled meats to reduce the risk of cancers of the colon, rectum, breast, prostate, kidney, and pancreas; (5) consumption of soy products during adolescence to reduce the risk of breast cancer in adulthood and to reduce the risk of recurrence and mortality for women previously treated for breast cancer; and (6) emphasizing fruits and vegetables to reduce risk of several common forms of cancer. Conclusion: By adopting the precautionary principle for nutrition research, this review aims to serve as a useful tool for practitioners and patients.

A Multicenter Randomized Controlled Trial of a Nutrition Intervention Program in a Multiethnic Adult Population in the Corporate Setting Reduces Depression and Anxiety and Improves Quality of Life: The GEICO Study

Purpose. To determine whether a plant-based nutrition program in a multicenter, corporate setting improves depression, anxiety, and productivity. Design. A quasi-experimental study examined the impact of diet on emotional well-being and productivity. Setting. The study was conducted in 10 corporate sites of a major U.S. insurance company. Subjects. There were 292 participants (79.8% women, 20.2% men), with body mass index ≥25 kg/m2 and/or previous diagnosis of type 2 diabetes. Intervention. Either weekly instruction in following a vegan diet or no instruction was given for 18 weeks. Measures. Depression and anxiety were measured using the Short Form-36 questionnaire. Work productivity was measured using the Work Productivity and Activity Impairment questionnaire. Analysis. Baseline characteristics were examined by t-test for continuous variables and χ2 test for categorical variables. Analysis of covariance models were adjusted for baseline covariates. Paired t-tests were used to determine within-group changes and t-tests for between-group differences. Results. In an intention-to-treat analysis, improvements in impairment because of health (p < .001), overall work impairment because of health (p = .02), non-work-related activity impairment because of health (p < .001), depression (p = .02), anxiety (p = .04), fatigue (p < .001), emotional well-being (p = .01), daily functioning because of physical health (p = .01), and general health (p = 0.02) in the intervention group were significantly greater than in the control group. Results were similar for study completers. Conclusion. A dietary intervention improves depression, anxiety, and productivity in a multicenter, corporate setting.

A worksite programme significantly alters nutrient intakes

OBJECTIVE To examine whether a worksite nutrition programme using a low-fat vegan diet could significantly improve nutritional intake. DESIGN At two corporate sites of the Government Employees Insurance Company, employees who were either overweight (BMI > or = 25 kg/m2) and/or had type 2 diabetes participated in a 22-week worksite-based dietary intervention study. SETTING At the intervention site, participants were asked to follow a low-fat vegan diet and participate in weekly group meetings that included instruction and group support (intervention group). At the control site, participants received no instruction (control group). At weeks 0 and 22, participants completed 3 d dietary records to assess energy and nutrient intake. SUBJECTS A total of 109 participants (sixty-five intervention and forty-four control). RESULTS In the intervention group, reported intake of total fat, trans fat, saturated fat and cholesterol decreased significantly (P < or = 0.001), as did energy and protein (P = 0.01), and vitamin B12 (P = 0.002), compared with the control group. Intake (exclusive of any use of nutritional supplements) of carbohydrate, fibre, vitamin C, magnesium and potassium increased significantly (P < or = 0.0001), as did that for beta-carotene (P = 0.0004), total vitamin A activity (P = 0.004), vitamin K (P = 0.01) and sodium (P = 0.04) in the intervention group, compared with the control group. CONCLUSIONS The present study suggests that a worksite vegan nutrition programme increases intakes of protective nutrients, such as fibre, folate and vitamin C, and decreases intakes of total fat, saturated fat and cholesterol.

Preparing to Prescribe Plant-Based Diets for Diabetes Prevention and Treatment

The number of people worldwide with type 2 diabetes is expected to double by 2030.1 In the United States, diabetes affects ~ 26 million people of all ages, about one-fourth of whom are not yet diagnosed.2 Despite the availability of a wide range of pharmacological treatments and the best efforts of diabetes educators and other health care professionals, good control of diabetes and its comorbidities remains elusive for much of the population, as evidenced by rates of cardiovascular morbidity and mortality that are two to four times higher than those of people who do not have diabetes.2 Although dietary habits and body weight play undisputed roles in type 2 diabetes, the question of what eating pattern best addresses glycemia, cardiovascular risk factors, and weight control remains controversial. The uniform, calorie-controlled diabetic diet plans of the past have been replaced by individualized meal-planning approaches, and in more recent years, nutrition guidance has focused on carbohydrate counting and minimizing saturated and trans fats. With the release of the U.S. Department of Agricultures 2010 Dietary Guidelines for Americans3 came praise for plant-based eating patterns, which have been extensively studied for weight management and disease prevention and treatment. Individuals following a plant-based eating pattern typically consume fewer calories and less fat, saturated fat, and cholesterol and have lower BMIs than nonvegetarians. They also consume more fiber, potassium, and vitamin C. In prospective studies of adults, compared to nonvegetarian eating patterns, vegetarian eating patterns have been associated with lower prevalence rates of type 2 diabetes,4 cardiovascular disease (CVD),5 hypertension,6 and obesity7,8 and reduced medical care usage.9 Both the American Academy of Nutrition and Dietetics and the American Diabetes Association (ADA) now include well-planned, plant-based eating patterns (vegetarian and vegan) as a meal-planning option in …